xxxxxxxxxx
iptables -A INPUT -p tcp --dport 8000 -s 1.2.3.4 -j ACCEPT
iptables -A INPUT -p tcp --dport 8000 -j DROP
xxxxxxxxxx
#Replace XXX with Port Number to allow
sudo iptables -I INPUT -p tcp -m tcp --dport 80 -j ACCEPT
#To persist iptable changes on reboot
sudo netfilter-persistent save